Protective covering for aircraft surfaces and the like



Feb 5, WQ HUNTER PROTECTIVE COVERING FOR AIRCRAFT SURFACES AND LIKE Filed Dec. s, 1943 Patented Feb. 5, 1946 .POTECTIV E COVERING FR.r AIRCRAFT vSURFACES AND THE LIKE V'Willson H. Hunter, Lakewood, Ohio,assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application December 3, 1943, Serial No. A512,718

7 Claims. (Cl. 244.--134)v This invention relates to protective coverings for the surfaces of structure such, for example, as aircraft and other vehicles, and is especially useful in its application to inatable protective coverings for preventing accumulation of ice on the leading edgel of wings and other airfoils and surfaces.

An airfoil, for example a wing'of an aircraft in night, may be functioning under cruising, driving, climbing and stalling conditions respectively, with accompanying variation in the aerodynamic forces at the leading edge of the air-l foil and especially in thearea of negative pressure produced by the airfoil. When the wing is provided with an inflatable protective covering of flexible material, such, for example, as resilient rubber-like material, this variation in aerodynamic forces tends at times to cause portions of the covering to lift away or to bulge 'objectionably from the wing surface in areas. in which is not secured directly to such surface.

By the present invention provision is made for removing the air from beneath the covering, thus increasing the adherence of the wing cover tol the wing surface and eliminating the possibility of its lifting or-bulging away from the'wing.

The withdrawal 'of the air beneath from thev covering is eected in a positive manner by suction which may be applied through a chamber of the covering. Thus strong suction can be utilized which is independent of variable external pressure upon the covering.

The chief objects of the invention are to provide eiectively for venting air from beneath the outer surface of the covering, to provide for effecting suction through the interior of the covering itself, to provide for utilizing the chamber of an inflatable covering during the intervals between iniations for applying the suction to the inner face of the covering, to provide this action While providing also against the transmission of pressure vfluid from the 'chamber to the under face of the covering, and to accomplish these results without requiring modification p of the wing surface or other structure upon which the covering is mounted. Y

These and other objects and advantages will be apparent from the following description, reference being made to the accompanying drawing, in which:

Fig. 1 `is a perspective view, with parts broken away, of an airplane Wing and a wing covering constructed in accordance with and embodying the invention. I f t Fig.' 2 is a bottom plan view of the covering of Figi, before its applicationrto the wing.

Fig.A 3' is a sectional view taken along line 3`v-`3r of Fig. 2. g i 'n Fig.' 4 is an enlarged'perspective view with'l parts broken. away of the valving portion Vci the covering. Y

Fig. 5 is a bottom plan view showing a modi. fled construction.

In the embodiment of they invention shown in Figs. 1 to 4 an inatable protective covering or shoe I0 of elastic construction is mounted upon an airfoil I2, such, for example, as an aircraft wing, the covering being preferably ina stretched condition chordwise of the wing and secured to the wing surface or its internal structure along upper and lower attaching margins I3 and M extending spanwise of the Wing. Metal fairing strips I5 may be providedl at the attaching margins of the covering I0. End margins I6 and the upper and lower attaching marginsv I3 and I4 of the`covering are adhered to the airfoil I2 as by a suitable adhesive, such, for example, as rubber cement, and the attaching` margins I3 and I4 are sealed to the wing surface by a clamp-A ing action of the fairing strips I5. y

The protective covering I0 includes inner and 'outer layers I1 andr I8 of ilexible material, such for example, as resilient rubber or other rubber-` like material. The inner layer I1 has a plurality of rectilinear lands or ribs I9y on the inner face at upper and lowerV stretchable portions 20 and 2|k of the covering andhas a smooth inner face at a central' distortable portion 22 of the covering, while the outer layer I8 has a smooth outer face and is continued over the fairing strips I5 to which it is adhered. The spanwise rectilinear channels between the lands I9 connect at intervals along their lengths with chordwise venting grooves 26. The covering alsoincludes a plurality of inatable tubes r23 to 25 preferably of resilient rubber or other rubber-like material which may be reinforced as by a distensible fabric, the tubes being sandwiched between jthe innerl and outer layersv I1 andy I8, as shown, for example in Fig. 1 and extending spanwise along the covering in the distortable portion 22. In the arrangement shown the tubes 23 to 25 are placed spanwise and parallel and side-by-side chordwise to the wing surface, but

any desired arrangement of tubes maybe used.

During operation of the ice-removing cover I0 each of the tubes 23 to 25 is alternately inilatedand deiiated by means of a power operated pump acting through an automatic timing con of the pump.

In accordance with the inventionadvantage,V

troller, for example of the type shown and described in my Patent No. 2,327,046. During inflation the tubes 23 to 25 are connected by means of suitable tubes 30 with the compression side of the pump and air is forcedin, Vcausing' the tubes to become inflated. On the other hand, during intervals ofideiiation each. tubefis con-- nected bythe automaticftiming controller with a source of suction which may be the exhaust side` is taken of the availability of the suctionTtoex'-,

. haust the air not only from the tubes but also from the space Ibetween thesurface of vtheair- Y foil lI2 and the protective covering' L0. Thiszis,

reduced at a specified time in the operating cycle by the exhaust action of the pump. The sealing of the margins I3, I4 and I6 of the cover to the surface of the airfoil will prevent entrance of air to the space between the Vairfoil and the covering. By the removal of air from this space a-1ower` pressure` beneath) the; covering vthan in its outer surface. can befmaintained and lifting or bulging of the covering is avoided. ,y

- In Fig. 5 modification is depicted in which the .lands orribs. I9. are constructed to extend chord- 1 wise;oi' the;zcovering. The channels between these i V lands connect with grooves 35 extending spanwise accomplished through apertures V28 connecting' the tube chambers with the venting groovesl at the under face of the covering by means of check Yvalves A2" which open these apertures when the. u

air pressure inside. the. tubes.. 23- and 25. isy reduced by the pump tota, degre'elower thanthatunder Athe protective coveringIIL One. f ormof Check valve is shown'inFig. 4. Itv consists of. a thin ilap..29, oi rubber` or..oth.er flexible lrubber .like material attachedeby.'vuloanization or by other suitable means asgfor example, rubber cement for l a.,y small. portionof, itsA periphery as. at 3.3 to the inside ofthe tube wall to function .asa hinge.

When pressurebelow theeiiap. exceeds the pressure; inside the, tube.. thel'ap.` lifts about its hinge away from the innersurface ofthe tube andthe aperture 2&. Whenairvi's frorcedinto they tube by, the4 pumpthepressurebecomes greater.v on.`

the tube sideoftheiiex-ible valve. ap than on theside nexttheopening '28... Thisfcauses. the flap toseat firmly. .overA the,opening4 28, and pre.- vents, passageof air; fromins'ider the tube through theQopeni-ng 28. tothe. inner'. face ofthe4 covering. A

In order to, prevent sealing. off. of'V part of the tube areaA around the ,openingsla I.because ofjcon.-

tact of portions of.A the, tubeJ surface throughA co1'- lapse of the tube wall, aporti'on olf. the wall. of the tube. in, the vicinity of. the, opening. 2B, may be, constructed withribsy or. lands v3i!" so that through the channelsbetweenthese ribsair mayy continue to. pass` awayfrom. the.. valve. so longY valvesl'l andthe tubeslB; andlito the exhaust` side .of ther pump. and nally, tothe atmosphere.. This. arrangemcntmakes for positiveandcer-tain. eliminationA of. air from. 'the space. between. the.l airfoil. I2 and; thepigtective .eovering ,.l.a;

Solong as the tubes. 2L3and 25am maintained; inoelated condition-the.. checkgvalve 21" Iferiiaiiisopenand the air maypassfreely fromthe.sparer between air.v foil andi. cover. to ,.thefatmosphereu. Whem hoy/.even thetiming controllerA connects the tubes .to the.. compression. side. ofY then pump.

pressure is ...built up .under thel..tubes 23;and25. greater in: degree than. exists betweenthejairfoil and thecov-cr.r Under these,circumstances,thel

a.i1: -from;,thel tubes, and the valves?.remainclosediV until the pressure inside tubes 23 and 25 is again o the; wing. A-t.. intervals apertures and check .valves-.21?, connect; these spanwise grooves xto the tubes-f23"andi 2 The elimination of air between Y the airfoil I Z'and this form of covering is similar` to thatwith the form in Fig. 5, first described. Thatziisthe air passes along the channels to the Ygrooves 35then through the hole. 28 and valve E'Iinto the tube23 or 2,5 thence through., theout.-V let, tubes'il to the exhaust side4 ofthe` pump or other source of" suction .and. finally to the atmosf phere.. Y

These andother variationsL may be madewith.-

out departing from the scope ofthe inventionas itis defined in therfollowing, claims.. e I I'claim; j 1. A protective covering cra surface'subiect `to forces tending to lift the coveringv fromV the suracein. the presence of air between the Vinner facer ofv said covering andsaid surface., said covering comprising between its inner and outerV faces achamberfor conducting' air; andI check valve means providing communication Abetween said chamber. andV the. inner face of. the covering. for flowl of" air from said' inner. face` into said' chamber andV for checking,y `iiow injthe reverse. direction. l f

2. A protective coveringfor a. surfa'cesubj'ect', toA forces tending tolift' the covering from. the surface in the presence o,f"a'ir,between the inner face of" said covering andr said suriacasaid .covering comprising an iniiatabl'e portion. providing f a chamber for conductingair,V and'check.I valve means providing .communication betweenfsaid chamber land the inner faceof thecovering. for flowk of air from saidinnerface into. said'chamf Y ber and for. checking flow in,the reverse direc.-

tion.

3; A protective.coveringr for. a surface, subject to forces tendingtoliftthe. covering,frorn ,the surface in the presence of air betweentheinner face ofisajdV covering andsaid surface, said'. covering comprising between; tsinnenand .outer facesga chamber for conducting air, theinner walLofsaid chamber .having a. passage through '.it. connecting v'alve rarresilient rubber alike .materialgajt .saidpsf sagepermitting yflowoilair from saidinner facev into saidfchamber 'and' preventingffIQw. in fthe reverse direction. e l

i1 A protective; coveringfor-a surface subject'v to forces; tending) tolit" thev lcovering `from 'the surfacelinthe presence of" air between-*the 'in-ner face of said covering and 'sa-idlsurrfaceisaidlcow ering having a. groovedinne-r aceland-compr-is-` ing.: between its: inner andi-cuter faces-.fafchamberf for conducting` air; `airclvalve .fmean's s. providing communicatibn between said chambieriand. the; srooved inner faceof; .the icoveringfforsfiow. ofa'ir proven-tinsf-flow.inthereverseidirectiom.Y -Y

5. A protective covering for an .Y airfoil said; covering having a grooved inner face and com- .'fromgsaid `rinpersia-ce;intrrsaidi'chamber andnfon prising between its inner and outer faces an infiatable tube having a passage through the Wall of said tube connecting with the grooved inner,

face of the covering, and a flap valve of resilient rubber-like material at said passage, said valve permitting flow of air from said inner face into said tube and preventing flow in the reverse direction.

6. A protective covering for a surface subject to aerodynamic action tending to lift the covering from the surface in the presence of air between the inner face of said covering and said surface,

said covering having a passage in its wall in communication with the inner face of the covering and means for permitting ow of air through covering while tending to close resiliently to resist iiow in the reverse direction.

WILLSON H. HUNTER. 

